The use of phenylbutazone in the horse
Article first published online: 14 JUN 2011
© 2011 Blackwell Publishing Ltd
Journal of Veterinary Pharmacology and Therapeutics
Volume 35, Issue 1, pages 1–12, February 2012
How to Cite
SOMA, L. R., UBOH, C. E. and MAYLIN, G. M. (2012), The use of phenylbutazone in the horse. Journal of Veterinary Pharmacology and Therapeutics, 35: 1–12. doi: 10.1111/j.1365-2885.2011.01299.x
- Issue published online: 6 JAN 2012
- Article first published online: 14 JUN 2011
- (Paper received 26 July 2010; accepted for publication 20 March 2011)
Soma, L. R., Uboh, C. E., Maylin G. M. The use of phenylbutazone in the horse. J. vet. Pharmacol. Therap. 35, 1–12.
This review presents a brief historical prospective of the genesis of regulated medication in the US racing industry of which the nonsteroidal anti-inflammatory drug (NSAID) phenylbutazone (PBZ) is the focus. It presents some historical guideposts in the development of the current rules on the use of PBZ by racing jurisdictions in the US. Based on its prevalent use, PBZ remains a focus of attention. The review examines the information presented in a number of different models used to determine the effects and duration of PBZ in the horse. They include naturally occurring lameness and reversible-induced lameness models that directly examine the effects and duration of the administration of various doses of PBZ. The review also examines indirect plasma and tissue models studying the suppression of the release of arachidonic acid-derived mediators of inflammation. The majority of studies suggest an effect of PBZ at 24 h at 4.4 mg/kg. This reflects and substantiates the opinion of many clinical veterinarians, many of whom will not perform a prepurchase lameness examination unless the horse is free of NSAID. This remains the opinion of many regulatory veterinarians responsible for the prerace examination of race horses that they wish to examine a horse without the possibility of an NSAID interfering with the examination and masking possible musculoskeletal conditions. Based on scientific studies, residual effects of PBZ remain at 24 h. The impact of sustained effect on the health and welfare of the horse and its contribution to injuries during competition remains problematic.